Put this snippet at the top of any Python file that is not the top level of your project to import to call code from other folders.
if __name__ == '__main__':
import os
import sys
sys.path.append(os.getcwd())
This project is intended as an example of how to import sibling packages when developing in Python. It is based on 3.6.8, I believe it should work on anything above Python 3.3 based on Notes from Nick Coghlan.
In no way do I claim this is the “Pythonic” or right way to make this work, but I was able to make it work consistently for my other development efforts and thought others may find this example useful.
Python has documentation on how to handle imports, but I found the examples were unhelpful during the development of a project. The examples using absolute paths seem to assume you are testing from the top level of your project, and not running individual modules which call a module found in another folder. There are also examples of Relative Imports however these seem to be just a way to avoid spelling out the full path of your modules, and not something you can leverage during development.
Included below is the project layout and examples of where you would insert the snippet from above. This project also contains files so that you can test the results of this yourself.
python-sibling-import/
top_level.py
sound/
second_level.py
effects/
echo.py
formats/
wav_write.py
{snippet}
{your code}
top_level.py can call down to lower packages without issue. However, if you want to run wav_write.py with a call to echo.py, this requires additional work to make functional. You can use the Snippet from above at the top of your lower level code to run individually, and still take advantage of what is written in another folder.
This leverages the Python OS function to get the Current Working Directory. Once it has your current working directory, it will add it to the System Path, which is a variable containing all the search locations for packages/modules to be loaded. When loading other packages in your project, it will treat them as if you were working from the top level folder.
The Snippet assumes that you are opening this project in your development environment from the top level or root of the project, and may not work otherwise. To modify the code to be opened from a lower level of the package, such as in second_level.py in Sound rather than PYTHON-SIBLING-IMPORT, the import statements would need to be modified to remove the inclusion of Sound.